This invention is concerned with the problem of nuclear fuel element failure resulting from a breach of the cladding container housing the fissionable fuel material. The container is employed to physically isolate and seal therein the fissionable fuel and fission products generated from any exposure to and/or contamination of the surrounding coolant such as water.
Entry of coolant water or vapor through a fracture in the container housing whereby it comes into contact with the enclosed fuel subjects the fuel to destructive reactions as well as leaking contaminating fission products out into the cooling medium of the overall system.